The present invention relates to an image processing system, a projector, a program, an information storage medium, and an image processing method.
When an image is displayed for a long time by an image display device such as a projector, color non-uniformity (including color non-uniformity due to luminance non-uniformity) are created in the image and the image gradually deteriorates.
This could happen when a projector is used to display an image continuously on a screen in a store or exhibition hall, for example. In such a case, the original display effect could be lost due to deterioration of components such as the liquid-crystal panel or a polarization plate during projection over a long period of time, which could generate color non-uniformity in the image.
A projector having a color non-uniformity correction means, such as that disclosed in Japanese Patent Application No. 2000-285933 (Japanese Patent Application Laid-Open No. 2002-90880) by way of example, is not configured for correcting color non-uniformity due to such time-related deterioration.
Causes of color non-uniformity due to time-related deterioration include the occurrence of light deficiencies due to time-related deterioration in a liquid-crystal light valve or polarization plate. The generation of a light deficiency could make an image that ought to be displayed as black appear to be blue.
If the projector projects an image in the R primary color in such a state, for example, there will be G and B color components within the R color so it is possible that the sensed data will be affected by colors other than R.
To remove the effects of ambient light such as artificial light, to ensure that the original way of viewing the desired image is reproduced, correction of the colors of the image is based on differential values between sensing information for a white monochromatic calibration image and sensing information for a black monochromatic calibration image.
However, if color non-uniformity occurs in the black monochromatic calibration image itself, it is possible that appropriate color correction cannot be applied because the above-described differential values are not accurate.
In addition, when an image is displayed in practice, the effects of ambient light such as artificial light or daylight can change the way in which the image is seen. Thus it is necessary to reduce the effects of ambient light by image processing, to ensure appropriate color reproduction of the image.